(i) Field of the Invention
This invention relates to novel phenylacetic ester derivatives and more particularly, to phenylacetic ester derivatives represented by the general formula (I) ##STR2## in which R represents hydrogen, a COR.sub.1 group (in which R.sub.1 represents an alkyl group or an alkenyl group), a ##STR3## group (in which R2 represents hydrogen, a halogen atom, a cyano group, a lower alkyl group or a phenyl group, R.sub.3 represents hydrogen, a lower alkyl group or a phenyl group, R.sub.4 represents a phenyl group which is unsubstituted or substituted with a lower alkyl group, a lower alkyloxy group, an acyloxy group, a hydroxy group or a halogen atom), a --CO--A--R.sub.5 group (in which A represents a single bond, an alkylene group having 1 or 2 carbon atoms or an alkyleneoxy group having 1 or 2 carbon atoms and R.sub.5 represents a phenyl group which is unsubstituted or substituted with a lower alkyl group, a lower alkyloxy group, an acyloxy group, a hydroxy group, a halogen atom, a nitro group, a benzoyl group or an alkylenedioxy group, and R' represents hydrogen or a methyl group. The invention also relates to the preparation of these derivatives.
(ii) Description of the Prior Art
Ketoprofen is one of drugs which are now widely used, as a non-steroidal antiphlogistic and analgesic agent, in the treatment of headache, toothache, lombago, myodinia and rheumatic diseases. However, it is known that when ketoprofen is orally dosed, side effects such as gastroenteric troubles are produced accompanied by ulceration. Ketoprofen may bring about unfavorable symptoms such as congestion and hemorrhage of stomach not only in the case of long-term administration such as in the medical treatment of rheumatic diseases, but also even in short-term administration. Accordingly, limitation is placed on the manner of administration and the dose.